1. Field of the Invention
This invention relates to a device for altering air flow and air pressure at the rear section of a tractor trailer or truck in order to increase fuel economy.
2. Description of Related Art
In most advanced countries in the world, including the United States and Europe, trucks carry a vast amount of cargo on a daily basis. In recent years the cost of diesel fuel and gasoline for trucks has increased dramatically, increasing the cost of shipping goods by truck. One factor that reduces gas mileage in tractor trailers and other trucks is air flow and air pressure (often referred to as drag) created at the rear end of the trailer or cargo chamber at highway speeds. Typically the cargo storage area of a truck and tractor trailer is a rectangular polyhedron to increase volume. The shape is not aerodynamically efficient for moving at highway speeds through air, resulting in drag, increasing full consumption. The drag increases as a function of velocity squared. The velocity, flow patterns, and pressures of air surrounding and passing by the truck trailer rear vertical surface reduces air flow efficiency resulting in lower gasoline or diesel mileage for the truck. Numerous devices are shown in the prior art to reduce air drag on the rear end section of a tractor trailer and other type truck.
The trailer section of a tractor trailer is typically shaped like a rectangular cargo shipping container. At highway and freeway driving speeds, trucks experience various air flow and pressure patterns including eddy currents generated at the rear surface of the trailer. Devices shown in the prior art have been disclosed to streamline the airflow as the air passes the rear end of the trailer during highway driving especially at top highway speeds. These devices tend to be complex in structure and operation and are costly to install. In different areas of the world tractor trailers and other trucks can carry additional loads at the rear end section of the trailer. The invention described herein is noncomplex in operation and is expandable manually or automatically and is collapsible and foldable for storage.
The invention described in this patent application alters air flow patterns at the rear end section of a trailer during highway driving while also allowing for additional load carrying areas on the top of the air deflection system mounted on the back of the trailer. This is important in some areas of the world where trucks are allowed to carry an extended load at the rear end of the trailer.